Answer: 709
Step-by-step explanation:
The formulas we use to find the required sample size :-
1.
, where = population standard deviation,
E = Margin of error .
z* = Critical value
2. , where p= prior estimate of population proportion.
3. If prior estimate of population proportion is unavailable , then we take p= 0.5 and the formula becomes
Given : Margin of error : E= 3% =0.03
Critical value for 95% confidence interval = z*= 1.96
A study conducted several years ago revealed that the percent of junior executives leaving within three years was 21%.
i.e. p=0.21
Then by formula 2., the required sample size will be :
[Round to the next integer.]
Hence, the required sample size of junior executives should be studied = 709